Method of fireproofing gasolines



Oct. 2, 1962 A. NUGEY 3,056,741

METHOD OF FIREPROOFING GASOLINES Filed July 8, 1955 IN VEN TOR.

g m/401v Ll. NU EY 7mm ATTORNEY United States 3,056,741 METHOD OF FIREPROOFING GASOLINES Anthony L. Nugey, 1271 Pierpont Sh, Rahway, NJ. Filed July 8, 1955, Ser- No. 520,840 1 Ciaini. (61. 208-670) This invention relates to a method for fireproofing motor, aviation and all other types of gasolines and other hydrocarbons. The chief object of this invention is to avoid fatalities upon the occurrence of accidents.

Great loss of life is caused by exploding gasoline tanks on motor-boats, automobiles, aircraft and other conveyances and for industrial uses. The worst cases arise when aircraft collide with one another during flights, or crash against mountains, superstructures, power transmission lines and the like. Such aircraft take fire from leaking, demolished or ruptured gasoline tanks and gasoline fuel systems. In other instances, the pilots intentionally or accidentally jettison the gasoline supply aboard and it falls on public or private properties.

This invention is useful with all types of volatile hydrocarbons for power or fuel purposes To describe the invention only two grades of gasolines will be considered, i.e., motor and aviation gasolines. It should be pointed out that even these two grades of gasolines have ditferent boiling points.

It is not possible to write the exact formula for gasolines in terms of the ratio of hydrogen and carbon, due to the fact that varying percentages of aromatics having the empirical formula C H are used in their manufacture. Similarly, the percentages of saturated aliphatics formula, C H present in gasoline blends vary widely also. Normally, isopentane is the lightest hydrocarbon fraction intentionally blended in motor and aviation gasolines. isopentane is used as a high-octane blending component and is the agent that brings the finished gasolines to their proper vapor pressures. In addition, small percentages of butane enter into the gasoline blends through poorly debutanized blending stocks.

The boiling ranges of gasolines are important since the volume percentage of the boiling points have a marked influence on the operating eificiencies of all kinds of internal combustion engines operating upon gasolines. To control the overall volatility of gasolines, maximum temperatures are specified for the points at which various percentages of gasolines have been evaporated. The present distillation specifications for motor gasolines are:

F. Initial boiling point, max 140 evaporated, max 221 evaporated, max 275 evaporated, max 356 End point, max 428 The present distillation specifications for aviation gasolines are:

F. 10% evaporated, max 167 50% evaporated, max 212 90% evaporated, max 275 End point, max 338 The initial boiling points and 10% points, which are limited by specifications to F. (motor gasolines) and 167 F. (aviation gasolines) respectively, determine the ease of engine starting, vapor-locking tendency, distribution in the engine manifolds and carburetor icing tendencies. Beyond these temperatures it simply alfects gasoline distribution, warm-up time, power output and fuel economies.

While the composition of gasolines is closely related to the ratio of 15% hydrogen to 85% carbons, it is well Patented Oct. 2, 1962 known that the number of carbons will increase above this empirical value as the percentage of aromatics are increased.

Gasolines are highly inflammable liquids. Their calorific value averages about 18,818 B.t.u./lb. Therefore, burning gasolines will develop tremendous heat when ignited, also tremendous energy is released when they explode.

Actually, it is not possible to calculate accurately the calorific value of gasolines, because the heat of formation must be deducted from the heat of combustion of the components which comprise the gasolines in order to arrive at the net heat of combustion of the hydrocarbons. The procedure for determining the heating values of gasolines made from theoretical blends is to use the experimentally determined net heating values for the various blending stocks and in this manner one arrives at the correct values of the heat of combustion of the hydrocarbons, i.e.z

This invention is a novel method for fireproofing gasolines used for fuel purposes in motorboats, automobiles, aircraft and the like, through the additions of low boiling point fluorinated hydrocarbons. When admixtures of fluorinated hydrocarbons are made with gasolines, the latter are rendered fireproof; such treated gasolines will not ignite, will not form explosive media, and in fact ignited gasoline will be quickly extinguished by adding fluorinated hydrocarbons.

Fluorinated hydrocarbons are saturated compounds and when admixed with gasolines cannot produce substitution products. They simply form two mutually soluble liquids (gasoline and fluorinated hydrocarbons) each with a different boiling point. By heating this mixture to the boiling point of fluorinated hydrocarbons, the vapor which distills oil, condensed and analyzed consists of pure fluorinated hydrocarbons and the remaining distillate will be pure gasoline.

The distillation operation for separating the two mutually soluble liquids (gasoline and fluorinated hydrocarbon) of different boiling points is accomplished most effectively in a fractionation apparatus, and this can be done by batch or continuous methods. Removal of the fluorinated hydrocarbons from the gasolines does not change the original properties of the gasoline, nor are the properties of the fluorinated hydrocarbons altered.

The fluorinated hydrocarbons within the scope of this invention are-trichlorotrifluoroethane, C Cl F and trichlorofluoromethane, CClgF is shown by the following chemical equations these fluorinated hydrocarbons will not produce substitution products when admixed in gasolines:

(a) Cn 2u+2 r ls a (gasoline) (gasoline) (gasoline) The control of the rate of evaporation of the lower boiling point fluorinated hydrocarbon (CCl F) is done by blending together the higher boiling point fluorinated hydrocarbon (C Cl F with CCl F and then adding this mixture into gasolines. Here again, this blend of fluorinated hydrocarbons will not produce substitution products when added to gasoline.

The fluorinated hydrocarbons which I have found suitable for fireproofing gasolines have these properties:

An important property of aviation gasolines is their freezing point. This is the temperature at which crystal lization of one or more of the gasoline components occurs. In high-flying altitudes temperatures may be encountered even lower than 100 F It stands to reason that aircraft when exposed to such critical low temperatures its gasoline supply, even in insulated supply tanks, will eventually approach the temperature of the atmosphere.

The freezing point of gasolines is approximately 76 R, which provides adequate protection against freeze-up of fuel systems or carburetor icings. However, it is well known that certain components of gasolines, particularly the aliphatics and aromatics are capable of dissolving from to 20 times as much water as do normal gasolines. Consequently, this undesirable property limits the maximum amount of aliphatics and aromatics additions in gasolines in order to maintain a freezing point of 60 F. for aviation gasolines. Appreciable quantities of accumulated water separates from the gasolines under low temperatures and thereby reduces the preferred safety factor with respect to the freezing point. This is the reason for frozen fuel systems and carburetor icings.

The addition of fluorinated hydrocarbons in gasolines materially reduces the freezing point of gasoline, which is an additional safety benefit in addition to fireproofing them. Where it is necessary to control the rate of evaporation as previously indicated, I have found that equal proportions of CCl F and C C1 F will produce a freezing point between 70 and 100 P. which is manifestly above that of gasolines.

In general, the specific amount of trichloromonofiuoromethane (CCI F) which I have found as satisfactory to fireproof gasolines will range between 10 and 60 percent of the weight of the gasoline to which it is added, depending on the volatility (distillation range of the gasoline), the vapor pressure and thermal properties of the gasoline. And to control the rate of evaporation of the low boiling point of the fluorinated hydrocarbon, I resort to the use of minor additions of high boiling point fluorinated hydrocarbon (C Cl F I have found it most satisfactory to prepare the blending of these two fluorinated hydrocarbons after actual operating conditions have been determined with respect to adequate fireproofing properties and the maintenance of sufliciently low freezing points under which aircrafts must operate.

The complete separation of fluorinated hydrocarbons from the gasolines in which the former have been added for making gasolines fireproof and to lower their freez ing points can be done by batch or continuous methods of separation. I prefer the continuous method because the conditions at any point of vapor separation are always constant.

The fluorinated hydrocarbons being more volatile than gasolines are readily and effectively separated (from the gasolines) by subjection of the two mutually soluble liquids (fluorinated hydrocarbons and gasolines) to heat, subsequently condensing the fluorinated hydrocarbon vapors and discharging their condensate into storage receptacles as rapidly as it is produced.

The continuous separation method requires a fractionation apparatus which is provided with a vapor heat exchanger at its uppermost position and a reboiler storage receptacle at the lowest position. The intermediate portion of the fractionation apparatus is provided with superimposed sections separated by plates. The plates are so designed that a constant reflux is discharged from the plate above on to the plate below, while the liberated vapors pass upward, with the least resistance from one section through the plate, then through the liquid on the plate and so on into succeeding sections.

The amount of heat input in the reboiler of the fractionation apparatus will depend on the amount of distillate removed (as fluorinated vapors) and the amount of liquid (gasoline and fluorinated hydrocarbons) returned as reflux. While any suitable means of heating the fractionation apparatus can be employed, I prefer to use either the hot exhaust gases from the engines or forced circulation of pre-heated air by these gases. This is the most economical means of heating the fractionation apparatus.

The heat exchanger provided in the top of the fractionation apparatus cools the fluorinated hydrocarbon vapors before their passage into the air condenser, and simultaneously preheats the incoming feed liquid (gasoline and fluorinated hydrocarbons) prior to being discharged into the fractionation apparatus.

The condenser is cooled by means of atmosphere air and its function is to remove the latent heat of vaporization of the fluorinated hydrocarbon liquid and the sensible heat to which this condensate is to be cooled. From the condenser this condensate is discharged into the storage tank where the liquid is stored for subsequent usage.

FIGURE 1 shows in outline apparatus for the separation of fluorinated hydrocarbons from gasolines, before the gasolines are used as engine fuel.

For a full understanding of this invention reference is made to accompanying drawing. The apparatus shown is a fractionation apparatus having a heat exchanger at top and a reboiler at the base. The intermediate section is provided with superimposed plates which function to carry out the separation of fluorinated hydrocarbons from the gasoline as previously described.

A suitable storage tank 1 is filled with fluorinated hydrocarbons and is preferably set above the gasoline storage tank 2. Where this is not possible, then a pump is used (not shown) to pump the fluorinated hydrocarbon into the gasoline storage tank. The main gasollne storage tank is provided with an internally built auxiliary gasoline chamber 3 separated from the interior of the tank 2 by a partition 4. From the chamber 3 pure gasoline is conducted through a pipe 5 having a valve 6 therein to one or more carburetors for starting of engines.

The tank 1 discharges into tank 2 through a valved connection 7, and the gasoline in the main part of the tank 2 is mixed with the fluorinated hydrocarbons and is conducted through a line of pipe 8 to the vapor heat exchanger 17. Adjacent the tank 2 is a valve 10 and a fuel feed pump 11 in the pipe or conduit 8. In the exchanger 17 the heat treatment of the mixed liquids separates the gasoline from the fluorinated hydrocarbons, the latter being returned to the tank 1 through a conduit 12. The gasoline with its combustibility and other fuel properties completely restored is drawn from the bottom through a pipe 13 and conducted to one or more carburotors and mixed with air preparatory to ignition. In the pipe 13 adjacent the reboiler is a check valve 14, and in line of the return pipe 12 is a condenser 15 which cools the fluorinated hydrocarbon vapors so that they are stored as liquids in the tank 1. The pipe 12' has a valve 16 in it between the tank 1 and the condenser 15. A drain valve for the pump 11 is indicated at 6a.

At the top the fractionation apparatus 9 is provided with a vapor heat exchanger 17 containing vertical pipes 18 open at their lower ends to the interior and at their upper ends to a header 19 connected with an outlet duct 19a leading to the return pipe 12, partitions 20 in which the lower and upper ends of the tubes 18 are fixed therein. The section 17 is connected to the interior of the fractionation apparatus 9 by a pipe 21 and in the fractionation apparatus below the section 17 are parallel transverse plates 22. The heater for the fractionation apparatus 9 comprises a jacket 23 surrounding lower end and a bank of pipes 24, which are open at both ends in the heater, but sealed from the interior of the boiler. The jacket receives exhaust gases through an inlet 26. In the line of pipe 8 is a two-Way control valve 27. The condenser 15 is air cooled with outside fins to radiate heat therefrom. A by-pass 28 from the two-Way valve 27 to the pipe 13 at a point beyond the valve 14 can be provided if desired, for feeding pure gasoline from tank 2 to engines by Way of pipe 13.

All of the apparatus described above is installed aboard the aircraft (or other transportation vehicle). Gasoline is pumped to the engine to start it from the compartment 3 through the line 5 and valve 6. At this time the valve 10 is closed. While the engine is operating with pure gasoline from auxiliary gasoline tank 3, the valve 27 is adjusted to permit the flow of fluorinated gasoline through the line 8 to top of vapor heat exchanger 17 from the tank 2. Hot exhaust gases (or preheated air) are directed through upper tubes 24 and reversed by header 23 into the lower tubes 24 and being exhausted at 26, so as to raise the temperature slightly above the boiling point of the fluorinated hydrocarbons.

When the tank 2 is refilled with gasoline, the valve 7 is opened to let down the fluorinated hydrocarbons to be admixed with the new supply of gasoline.

The tanks 1 and 2 will have vacuum and pressure relief valves 29 and all the valves will have operating members within easy reach of the pilot of the aircraft,

or driver of the automobile carrying the apparatus. Ordinarily the tank 1 will be about half the size of the tank 2. The apparatus is quite simple and can be installed conveniently in conjunction with the usual equipment for internal combustion engines. The addition of fluorinated hydrocarbons to gasoline renders the gasoline even more resistant to freezing.

The same apparatus and method can be utilized for fuels heavier than gasoline to avoid disastrous fires when accidents take place.

Having described my invention, what I believe to be new is:

The method of treating gasoline which consists in mixing it with fluorinated hydrocarbons when in storage, and thus rendering it non-combustible, transferring the mixture thus formed from the place of storage to an enclosed space, heating the mixture in said space to vaporize and separate the fluorinated hydrocarbons from the mixture, maintaining the gasoline in liquid condition during such heating, condensing and recovering the fluorinated hydrocarbons and storing them adjacent a body of gasoline for further use in such mixing, and transferring the de-fluorinated gasoline to a place of ignition, as engine fuel.

References fited in the file of this patent UNITED STATES PATENTS 41,871 Thirault Mar. 8, 1864 159,665 Edgerton Feb. 9, 1875 1,443,742 Hess Jan. 30, 1923 1,926,396 Midgley et al Sept. 12, 1933 2,021,98 1 Bichowski Nov. 26, 1935 2,136,767 Terres et al. Nov. 15, 1938 2,388,040 Clark Oct. 30; 1945 

